Information transport networks are well known in the art and function to transmit information such as computer data between various computer systems operably coupled to the information network. Client networks may be sending to and receiving information from the information transport networks, for example, through one or more routers. Generally, data transport networks are defined as having multiple “layers” that combine to make a network. For example, one standard that describes a multi-layer model is the International Telecommunication Union recommendation ITU-T X.200 (07/94), entitled “Information technology—Open Systems Interconnection—Basic Reference Model: The basic model.” The Open Systems Interconnection (OSI) Model contains the following seven layers: the Application Layer (layer 7), the Presentation Layer (layer 6), the Session Layer (layer 5), the Transport Layer (layer 4), the Network Layer (layer 3), the Data Link Layer (layer 2), and the Physical Layer (layer 1). The model may also include a Layer Zero containing transmission media. Layers may be generally referred to as electronic layers (also known as digital layers) and optical layers.
The electronic/digital layer and the optical layer each contain multiple sub-layers. The optical layer provides optical connections, also referred to as optical channels or lightpaths, to other layers, such as the electronic layer. The optical layer performs multiple functions, such as monitoring network performance, multiplexing wavelengths, and switching and routing wavelengths. Additional structure, architecture, and modeling are further described in the International Telecommunication Union recommendations, including ITU-T G.709, ITU-T G.872, and ITU-T G.805, which are well known in the art.
Typically, packet switched network systems are interconnected using wavelengths from the optical transmission backbone (the transport layer) that may contain a mix of wave-division multiplexing (WDM) (optical) transmission and/or Optical Transport Network (OTN) (Digital) switching technologies and/or packet switching technologies. Conventionally, traffic engineers may set or pre-engineer one or more paths for a data traffic flow through the packet switched layer of the network, or the path may be computed using native routing protocols within the packet switched layer.
A switched network usually includes multiple switch nodes (also referred to as “nodes”) which are connected by communication links and arranged in a topology referred to in the art as a “mesh network”. Within the mesh network, user traffic can be transported between any two locations using predefined connections specifying particular links and/or switch nodes for conveying the user traffic. Shared Mesh Protection (SMP) is a common protection and recovery mechanism in mesh networks, where multiple services can share the same set of network resources (such as bandwidth or timeslots on a common path) for protection purposes. Mesh networks utilizing Shared Mesh Protection may be referred to as shared mesh networks.
The switch nodes in the mesh network are each provided with a control module. The control modules of the switch nodes function together to aid in the control and management of the mesh networks. The control modules can run a variety of protocols for conducting the control and management of the mesh networks. One prominent protocol is referred to in the art as “Generalized Multiprotocol Label Switching (GMPLS)”.
Generalized Multiprotocol Label Switching (GMPLS) is a type of protocol which extends multiprotocol label switching to encompass network schemes based upon time-division multiplexing (e.g. SONET/SDH, PDH, G.709), wavelength multiplexing, and spatial switching (e.g. incoming port or fiber to outgoing port or fiber). Multiplexing, such as time-division multiplexing is when two or more signals or bit streams are transferred over a common channel. Wave-division multiplexing (WDM) is a type of multiplexing in which two or more optical carrier signals are multiplexed onto a single optical fiber by using different wavelengths (that is, colors) of laser light.
Generalized Multiprotocol Label Switching includes multiple types of label switched paths including protection and recovery mechanisms which specifies predefined (1) working connections within a mesh network having multiple nodes and communication links for transmitting data between a headend node and a tailend node; and (2) protecting connections specifying a different group of nodes and/or communication links for transmitting data between the headend node to the tailend node in the event that one or more of the working connections fail. Working connections may also be referred to as working paths. Protecting connections may also be referred to as recovery paths and/or protecting paths and/or protection paths. A first node of a path may be referred to as a headend node or a source node. A last node of a path may be referred to as a tailend node or end node or destination node. Typically, the headend node or tailend node initially selects to receive data over the working connection (such as an optical channel data unit label switched path) and then, when a working connection fails, the headend node or tailend node selects a protecting connection for passing data within the mesh network. The set up and activation of the protecting connections may be referred to as restoration or protection. Protection mechanisms, where network resources act as backup for working connections, have been in use for some time.
Routing and topology management protocols may also be used with GMPLS. For example, under OSPF protocols, typically each node in a network maintains a database of the network topology and the current set of resources available, as well as the resources used to support traffic. In the event of any changes in the network, or simply periodically, the node floods the updated topology information to all the network nodes. The nodes use the database information to chart routes through the network.
In current systems, to set up a connection in an information transport network, nodes in the network exchange messages with other nodes in the network (for example, by using RSVP or RSVP-TE signaling protocols). Resources required for the connection are reserved and switches inside a node of the network are pre-configured to forward information from certain input ports to certain output ports. Information sent by signaling protocols are often in a type-length-value (TLV) format. The same protocols may also be used to take down connections in the network when the connections are no longer needed.
Current systems typically control configuration, protection and recovery mechanisms at the digital level in the network. Particularly, protection resources are typically controlled by the nodes and may be dedicated to act as backup paths (protection paths) in the event of a failure in the network resources carrying data traffic through the working paths. For example, in Shared Mesh Protection (SMP) the headend node or tailend node initially sets up one or multiple protection paths for a particular working path. During setup, network resources, for example, nodes, communication links, and timeslots, are specified for each path. Each protection path may reserve the timeslots on the intermediate nodes of the protection path, but does not actually configure them until needed. The timeslots may be shared by multiple protection paths.
The implementation of recovery in the network after a failure generally includes the source and/or destination nodes in the path digitally switching to the reserved nodes and communication links outside of the original working path to reroute data traffic through the network. The nodes may have limited knowledge of the bandwidth resources available in the network. Additionally, it may be inefficient to dedicate and reserve backup paths and to switch to those backup nodes.
As information transport systems move to integrated optical and digital network models, systems and methods are needed to orchestrate network resources and to configure and control network elements across multi-layers in the network, for example, for protection and restoration services.